The post-industrial European city is characterized by dispersed urbanization, resulting in increased travel, substantial use of land, social disparities and costs that are unsustainable in the long term. Consequently, most European countries have set the goal of limiting urban sprawl by prioritizing increased density in already built-up areas. To achieve this goal, it is not enough to build new buildings in the urban lots that are still available. Efforts to increase the density of existing neighborhoods are also needed. These actions represent an important opportunity for ensuring sustainability through the simultaneous integration of socio-cultural, economic, and environmental criteria in our cities. This paper presents the evaluative approach applied to a case study carried out in the Fleurettes neighborhood, located near the train station in Lausanne, Switzerland. It demonstrates how carrying out a structured sustainability assessment of an existing neighborhood as well as a multi-criteria comparison of three possible scenarios using a tool recently developed known as SméO may truly help the decision-making process when choosing an operational strategy.